{"id":4837,"date":"2026-06-03T06:24:38","date_gmt":"2026-06-03T05:24:38","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/further-substitution\/"},"modified":"2026-10-25T12:11:07","modified_gmt":"2026-10-25T12:11:07","slug":"further-substitution","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/further-substitution\/","title":{"rendered":"Further Substitution"},"content":{"rendered":"\n<section class=\"ols-revision-page ols-further-substitution-page\">\n  <style>\n    .ols-revision-page {\n      --navy: #1C244B;\n      --blue: #2563eb;\n      --soft-blue: #eef4ff;\n      --soft-red: #fff7f7;\n      --soft-purple: #f7f0ff;\n      --soft-green: #f0f7f1;\n      --soft-yellow: #fff8e6;\n      --red: #c81e1e;\n      --gold: #c9973a;\n      --green: 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.ols-linkedin-pill::before {\n      content: \"\";\n      position: absolute;\n      top: 0;\n      left: -120%;\n      width: 100%;\n      height: 100%;\n      background: linear-gradient(120deg, rgba(255,255,255,0) 0%, rgba(255,255,255,0.28) 50%, rgba(255,255,255,0) 100%);\n      transition: left 0.7s ease;\n    }\n\n    .ols-linkedin-pill:hover {\n      transform: translateY(-3px) scale(1.03);\n      box-shadow: 0 16px 34px rgba(10,102,194,0.34), 0 0 0 6px rgba(10,102,194,0.10);\n      color: #ffffff !important;\n    }\n\n    .ols-linkedin-pill:hover::before { left: 120%; }\n\n    .ols-linkedin-icon {\n      width: 18px;\n      height: 18px;\n      display: block;\n      flex-shrink: 0;\n    }\n\n    .ols-note-card.soft { background: linear-gradient(135deg, #ffffff 0%, var(--soft-red) 100%); }\n    .ols-note-card.purple { background: linear-gradient(135deg, #ffffff 0%, var(--soft-purple) 100%); }\n    .ols-note-card.green { background: linear-gradient(135deg, #ffffff 0%, var(--soft-green) 100%); }\n    .ols-note-card.yellow { background: linear-gradient(135deg, #ffffff 0%, var(--soft-yellow) 100%); }\n\n    .ols-note-title {\n      display: flex;\n      align-items: center;\n      gap: 14px;\n      margin-bottom: 20px;\n    }\n\n    .ols-note-icon {\n      width: 52px;\n      height: 52px;\n      border-radius: 16px;\n      background: var(--navy);\n      color: #ffffff;\n      display: grid;\n      place-items: center;\n      font-size: 24px;\n      font-weight: 800;\n      flex-shrink: 0;\n    }\n\n    .ols-note-title h2,\n    .ols-h5p-card h2,\n    .ols-related-card h2,\n    .ols-faq-card h2 {\n      margin: 0;\n      font-size: clamp(28px, 3.5vw, 42px);\n      line-height: 1.15;\n      font-weight: 800;\n      color: #111827;\n      letter-spacing: -0.03em;\n    }\n\n    .ols-h5p-card h2,\n    .ols-related-card h2,\n    .ols-faq-card h2 { margin-bottom: 14px; }\n\n    .ols-note-card p,\n    .ols-note-card li {\n      font-size: clamp(15px, 1.25vw, 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anywhere;\n    }\n\n    .ols-equation-grid {\n      display: grid;\n      grid-template-columns: 1fr;\n      gap: 14px;\n      margin-top: 20px;\n    }\n\n    .ols-table-wrap {\n      overflow: hidden;\n      border-radius: 22px;\n      border: 1px solid var(--border);\n      background: #ffffff;\n      margin-top: 18px;\n    }\n\n    .ols-table {\n      width: 100%;\n      border-collapse: collapse;\n      table-layout: fixed;\n    }\n\n    .ols-table th {\n      background: var(--navy);\n      color: #ffffff;\n      padding: 16px;\n      text-align: left;\n      font-size: clamp(14px, 1.2vw, 17px);\n      font-weight: 600;\n      overflow-wrap: anywhere;\n      word-break: normal;\n    }\n\n    .ols-table td {\n      padding: 16px;\n      border-bottom: 1px solid var(--border);\n      font-size: clamp(14px, 1.15vw, 16px);\n      line-height: 1.45;\n      color: var(--body-text);\n      vertical-align: top;\n      overflow-wrap: anywhere;\n      word-break: normal;\n    }\n\n    .ols-table tr:last-child td { border-bottom: none; }\n\n    .ols-h5p-card { background: linear-gradient(135deg, #ffffff 0%, #f7f0ff 100%); }\n\n    .ols-h5p-frame {\n      margin-top: 22px;\n      padding: 18px;\n      border-radius: 24px;\n      background: #ffffff;\n      border: 1px solid var(--border);\n      box-shadow: inset 0 0 0 1px rgba(28, 36, 75, 0.03);\n    }\n\n    .ols-faq-card { background: linear-gradient(135deg, #ffffff 0%, #f8fbff 100%); }\n\n    .ols-faq-list {\n      display: grid;\n      gap: 14px;\n      margin-top: 20px;\n    }\n\n    .ols-faq-item {\n      background: #ffffff;\n      border: 1px solid var(--border);\n      border-radius: 18px;\n      padding: 18px 20px;\n      box-shadow: var(--inner-shadow);\n    }\n\n    .ols-faq-item h3 {\n      margin: 0 0 8px;\n      font-size: 18px;\n      line-height: 1.35;\n      color: var(--navy);\n    }\n\n    .ols-faq-item p { margin: 0; }\n\n    .ols-related-grid {\n      display: grid;\n      grid-template-columns: repeat(3, minmax(0, 1fr));\n      gap: 16px;\n      margin-top: 18px;\n    }\n\n    .ols-related-item {\n      border: 1px solid var(--border);\n      border-radius: 18px;\n      padding: 18px;\n      background: #ffffff;\n      color: var(--navy);\n      text-decoration: none;\n      font-weight: 600;\n      line-height: 1.5;\n      transition: transform 0.2s ease, box-shadow 0.2s ease;\n    }\n\n    .ols-related-item:hover {\n      transform: translateY(-2px);\n      box-shadow: 0 10px 22px rgba(28, 36, 75, 0.08);\n    }\n\n    @media (max-width: 1050px) {\n      .ols-main { max-width: none; }\n      .ols-related-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }\n    }\n\n    @media (max-width: 760px) {\n\n      .ols-title-card,\n      .ols-note-card,\n      .ols-h5p-card,\n      .ols-related-card,\n      .ols-faq-card {\n        padding: 24px 18px;\n        border-radius: 22px;\n      }\n\n      .ols-note-title { align-items: flex-start; }\n\n      .ols-author {\n        align-items: flex-start;\n        gap: 16px;\n      }\n\n      .ols-author-avatar-img {\n        width: 72px;\n        height: 72px;\n      }\n\n      .ols-author-title { font-size: 23px; }\n      .ols-author-description { font-size: 15px; }\n\n      .ols-table-wrap {\n        border-radius: 20px;\n        overflow: hidden;\n      }\n\n      .ols-table,\n      .ols-table thead,\n      .ols-table tbody,\n      .ols-table th,\n      .ols-table td,\n      .ols-table tr {\n        display: block;\n        width: 100%;\n      }\n\n      .ols-table thead { display: none; }\n\n      .ols-table tr {\n        border-bottom: 1px solid var(--border);\n        background: #ffffff;\n      }\n\n      .ols-table tr:last-child { border-bottom: none; }\n\n      .ols-table td {\n        display: grid;\n        grid-template-columns: minmax(120px, 38%) minmax(0, 1fr);\n        gap: 12px;\n        align-items: start;\n        border-bottom: 1px solid rgba(28, 36, 75, 0.08);\n        padding: 14px;\n        overflow-wrap: anywhere;\n      }\n\n      .ols-table td:last-child { border-bottom: none; }\n\n      .ols-table td::before {\n        content: attr(data-label);\n        font-weight: 700;\n        color: var(--navy);\n        overflow-wrap: anywhere;\n      }\n    }\n  <\/style>\n\n  <aside class=\"ols-sidebar\">\r\n  <div class=\"ols-sidebar-header\">\r\n    <h3>Revision Notes<\/h3>\r\n    <p>A Level Chemistry<\/p>\r\n  <\/div>\r\n\r\n  <div class=\"ols-topic-group\">\r\n    <h4>Topic 6 Organic Chemistry I<\/h4>\r\n\r\n    <ul class=\"ols-topic-list\">\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/\">Introduction to Organic Chemistry<\/a>\r\n\r\n        <ul class=\"ols-subtopic-list\">\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/iupac-rules\/\">IUPAC Rules<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/alkene\/\">Alkene<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/alcohol\/\">Alcohol<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/halogenoalkanes\/\">Halogenoalkanes<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/aldehyde\/\">Aldehyde<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/ketone\/\">Ketone<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/carboxylic-acid\/\">Carboxylic Acid<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/ester\/\">Ester<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/isomerism\/\">Isomerism<\/a>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/\">Alkanes<\/a>\r\n\r\n        <ul class=\"ols-subtopic-list\">\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/crude-oil\/\">Alkanes from Crude Oil<\/a>\r\n\r\n            <ul class=\"ols-subtopic-list\">\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/crude-oil\/fractional-distillation\/\">Fractional Distillation<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/crude-oil\/cracking\/\">Cracking<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/crude-oil\/reforming\/\">Reforming<\/a>\r\n              <\/li>\r\n            <\/ul>\r\n          <\/li>\r\n\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/fuel\/\">Alkanes as Fuel<\/a>\r\n\r\n            <ul class=\"ols-subtopic-list\">\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/fuel\/combustion\/\">Combustion<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/fuel\/oxides-of-sulfur\/\">Oxides of Sulfur<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/fuel\/oxides-of-nitrogen\/\">Oxides of Nitrogen<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/fuel\/catalytic-converter\/\">Catalytic Converter<\/a>\r\n              <\/li>\r\n            <\/ul>\r\n          <\/li>\r\n\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/alternative-fuel\/\">Alternative Fuel<\/a>\r\n          <\/li>\r\n\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/\">Reactions of Alkanes<\/a>\r\n\r\n            <ul class=\"ols-subtopic-list\">\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/free-radical-substitution\/\">Free Radical Substitution<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/initiation\/\">Initiation<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/propagation\/\">Propagation<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/termination\/\">Termination<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/further-substitution\/\">Further Substitution<\/a>\r\n              <\/li>\r\n            <\/ul>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/\">Alkenes<\/a>\r\n\r\n        <ul class=\"ols-subtopic-list\">\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/alkene-bonding\/\">Alkene Bonding<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/geometric-isomerism\/\">Geometric Isomerism<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/electrophilic-addition-mechanism\/\">Electrophilic Addition Mechanism<\/a>\r\n          <\/li>\r\n\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/\">Reactions of Alkenes<\/a>\r\n\r\n            <ul class=\"ols-subtopic-list\">\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/halogens\/\">Halogens<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/hydrogen-halide\/\">Hydrogen Halide<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/bromine-water\/\">Bromine Water<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/hydrogen\/\">Hydrogen<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/steam\/\">Steam<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/\">KMnO4<\/a>\r\n              <\/li>\r\n            <\/ul>\r\n          <\/li>\r\n\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/polymerisation-reactions\/\">Polymerisation Reactions<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/polymer-waste\/\">Polymer Waste<\/a>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/halogenoalkanes\/\">Halogenoalkanes<\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alcohols\/\">Alcohols<\/a>\r\n      <\/li>\r\n\r\n    <\/ul>\r\n  <\/div>\r\n\r\n  <div class=\"ols-topic-group\">\r\n    <h4>Next Topics<\/h4>\r\n\r\n    <ul class=\"ols-topic-list\">\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-7-modern-analytical-techniques-i\/\">Topic 7 Modern Analytical Techniques I<\/a>\r\n      <\/li>\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-5-formulae-equations-and-amounts-of-substance\/\">Topic 5 Formulae, Equations &amp; Amounts<\/a>\r\n      <\/li>\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-4-inorganic-chemistry-and-the-periodic-table\/\">Topic 4 Inorganic Chemistry &amp; The Periodic Table<\/a>\r\n      <\/li>\r\n    <\/ul>\r\n  <\/div>\r\n<\/aside>\r\n\r\n<script>\r\n(function() {\r\n  function normalisePath(path) {\r\n    return String(path || '')\r\n      .split('?')[0]\r\n      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href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/\">Revision Notes<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/\">A Level Chemistry<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/\">Edexcel<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/\">Topic 6 Organic Chemistry I<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/free-radical-substitution\/\">Reactions of Alkanes<\/a> \/\n        <span>Further Substitution<\/span>\n      <\/nav>\n\n      <header class=\"ols-title-card\">\n        <h1>Further Substitution<\/h1>\n        <p class=\"ols-page-intro\">A concise Edexcel A Level Chemistry revision guide to further substitution in the free-radical substitution of methane, including excess chlorine, formation of CH<sub>2<\/sub>Cl<sub>2<\/sub>, CHCl<sub>3<\/sub> and CCl<sub>4<\/sub>, and the overall equation for complete chlorination.<\/p>\n\n        <div class=\"ols-badges\">\n          <div class=\"ols-badge\">Paper 2<\/div>\n          <div class=\"ols-badge\">Topic 6: Organic Chemistry I<\/div>\n          <div class=\"ols-badge\">9CH0\/02<\/div>\n        <\/div>\n      <\/header>\n<!-- 3D card: further-substitution-methane (22 Oct 2026) -->\n<!-- Copyright (c) 2026 Dr. Mohammed Al-Fatah, onlinelearningsystem.net. 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border:1px solid rgba(28,36,75,0.18);\n}\n.ols-fsub-001 .fsub-key i.k-ball{border-radius:50%;}\n\n@media (max-width:760px){\n  .ols-fsub-001{padding:26px; border-radius:22px;}\n  .ols-fsub-001 h2.fsub-title{font-size:20.5px;}\n  .ols-fsub-001 p.fsub-sub{font-size:13.5px;}\n  .ols-fsub-001 .fsub-stage{height:400px;}\n  .ols-fsub-001 .fsub-rowlab{min-width:100%;}\n  .ols-fsub-001 .fsub-seg button{padding:9px 13px; font-size:13px;}\n  .ols-fsub-001 .fsub-lab{font-size:10.5px; padding:4px 8px;}\n  .ols-fsub-001 .fsub-lab.l-part{font-size:9.5px; padding:3px 7px;}\n  .ols-fsub-001 .fsub-lab.l-read{font-size:12px; padding:5px 9px;}\n  .ols-fsub-001 .fsub-caption{font-size:10.5px; padding:5px 9px; max-width:64%;}\n  .ols-fsub-001 .fsub-badge{font-size:10.5px; padding:4px 9px;}\n  .ols-fsub-001 .fsub-badge.b-eq{font-size:11px;}\n  .ols-fsub-001 .fsub-badges{max-width:calc(100% - 28px);}\n  .ols-fsub-001 .fsub-info{padding:18px;}\n}\n\/* on a phone the caption needs the full top row, so the drag hint goes *\/\n@media (max-width:480px){\n  .ols-fsub-001 .fsub-hint{display:none;}\n  .ols-fsub-001 .fsub-caption{max-width:calc(100% - 28px);}\n}\n@media (prefers-reduced-motion:reduce){\n  .ols-fsub-001 .fsub-seg button,.ols-fsub-001 .fsub-pill{transition:none;}\n}\n\n.ols-cc-fsub-001{\n  font-family:'Poppins',system-ui,-apple-system,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;\n  margin:10px auto 0; text-align:center; font-size:11px; font-style:italic; color:#aab0c0;\n}\n.ols-cc-fsub-001 a{color:#aab0c0; text-decoration:none;}\n.ols-cc-fsub-001 a:hover{text-decoration:underline;}\n.ols-fsub-001 .fsub-seg button{display:inline-flex; align-items:center;}\n.ols-fsub-001 .fsub-seg button .fsub-n{display:inline-flex; align-items:center; justify-content:center; width:20px; height:20px; margin-right:9px; border-radius:50%; font-size:11px; font-weight:600; background:rgba(37,99,235,0.10); color:#2563eb; flex:0 0 auto;}\n.ols-fsub-001 .fsub-seg button[aria-pressed=\"true\"] .fsub-n{background:#ffffff; color:#2563eb;}\n<\/style>\n\n<div class=\"fsub-head\">\n  <h2 class=\"fsub-title\">Further Substitution: Why Chlorination Gives a Mixture<\/h2>\n  <p class=\"fsub-sub\">Choose a step to watch chlorine radicals keep replacing hydrogen atoms, then see the isomers from propane and the mixture that results.<\/p>\n<\/div>\n\n<div class=\"fsub-stage\" id=\"fsubStage\">\n  <canvas class=\"fsub-canvas\" id=\"fsubCanvas\"><\/canvas>\n  <div class=\"fsub-overlay\" id=\"fsubOverlay\"><\/div>\n  <div class=\"fsub-caption\" id=\"fsubCaption\"><\/div>\n  <div class=\"fsub-hint\" id=\"fsubHint\">Drag to rotate<\/div>\n  <div class=\"fsub-badges\" id=\"fsubBadges\"><\/div>\n<\/div>\n\n<div class=\"fsub-controls\">\n  <div class=\"fsub-row\">\n    <span class=\"fsub-rowlab\">Step<\/span>\n    <div class=\"fsub-seg\" role=\"group\" aria-label=\"Step\">\n      <button type=\"button\" data-step=\"1\" aria-pressed=\"true\"><span class=\"fsub-n\">1<\/span>CH\u2084 \u2192 CH\u2083Cl<\/button>\n      <button type=\"button\" data-step=\"2\" aria-pressed=\"false\"><span class=\"fsub-n\">2<\/span>Again: CH\u2082Cl\u2082<\/button>\n      <button type=\"button\" data-step=\"3\" aria-pressed=\"false\"><span class=\"fsub-n\">3<\/span>On to CCl\u2084<\/button>\n      <button type=\"button\" data-step=\"4\" aria-pressed=\"false\"><span class=\"fsub-n\">4<\/span>Propane: isomers<\/button>\n      <button type=\"button\" data-step=\"5\" aria-pressed=\"false\"><span class=\"fsub-n\">5<\/span>The mixture<\/button>\n    <\/div>\n  <\/div>\n\n  <div class=\"fsub-row\">\n    <span class=\"fsub-rowlab\">View<\/span>\n    <button type=\"button\" class=\"fsub-pill\" id=\"fsubResetV\">Reset view<\/button>\n  <\/div>\n<\/div>\n\n<div class=\"fsub-info\">\n  <h3 id=\"fsubInfoTitle\"><\/h3>\n  <p id=\"fsubInfoText\"><\/p>\n  <div class=\"fsub-facts\" id=\"fsubFacts\"><\/div>\n  <div class=\"fsub-key\">\n    <span><i class=\"k-ball\" style=\"background:#464a54\"><\/i>Carbon<\/span>\n    <span><i class=\"k-ball\" style=\"background:#ececf0\"><\/i>Hydrogen<\/span>\n    <span><i class=\"k-ball\" style=\"background:#34aa48\"><\/i>Chlorine<\/span>\n    <span><i class=\"k-ball\" style=\"background:#f6c426\"><\/i>Unpaired electron<\/span>\n  <\/div>\n<\/div>\n\n<script src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/JS\/further-substitution-methane.js?v=20261025p\"><\/script>\n<\/section>\n\n<p class=\"ols-cc-fsub-001\">&copy; Dr. Mohammed Al-Fatah &#8211; <a href=\"https:\/\/www.onlinelearningsystem.net\" target=\"_blank\" rel=\"noopener\">onlinelearningsystem.net<\/a><\/p>\n\n\n      <article class=\"ols-note-card soft\" id=\"article\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">1<\/div>\n          <h2>What Is Further Substitution?<\/h2>\n        <\/div>\n\n        <p><strong>Further substitution<\/strong> occurs when the halogenoalkane product from an earlier free-radical substitution step reacts again with chlorine. This means additional hydrogen atoms are replaced by chlorine atoms.<\/p>\n        <p>In the chlorination of methane, the first substitution forms chloromethane, CH<sub>3<\/sub>Cl. If chlorine is present in excess, CH<sub>3<\/sub>Cl can undergo further substitution to form more highly chlorinated products.<\/p>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Key idea:<\/strong> Further substitution is still a free-radical substitution process. The molecule already contains chlorine, but remaining C-H bonds can still be substituted.<\/p>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">2<\/div>\n<h2>Before You Start<\/h2>\n<\/div>\n<p>This page builds on the three stages of free-radical substitution.<\/p>\n<ul class=\"ols-list\">\n<li>Methane reacts with chlorine in UV light to give chloromethane and hydrogen chloride.<\/li>\n<li>Each propagation step swaps one radical for another.<\/li>\n<li>Methane has four C-H bonds, and each can be replaced by a C-Cl bond.<\/li>\n<li>An excess of one reactant leaves some of it unused at the end.<\/li>\n<\/ul>\n<\/article>\n<section class=\"ols-h5p-card ols-h5p-inline ols-h5p-recap\">\n<span class=\"ols-h5p-kicker\">Before you start<\/span>\n<h2>GCSE Recap: Displacement, Balancing and Excess<\/h2>\n<p>Check the GCSE ideas about replacing atoms, balancing and excess reactants that this page builds on.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-content\" data-content-id=\"1290\"><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">3<\/div>\n          <h2>Why Excess Chlorine Causes Further Substitution<\/h2>\n        <\/div>\n\n        <p>When chlorine is present in excess, there are enough chlorine molecules and chlorine radicals for the reaction to continue beyond the first substitution product.<\/p>\n        <p>As more hydrogen atoms are replaced, a mixture of chlorinated products can form. These include dichloromethane, trichloromethane and tetrachloromethane.<\/p>\n\n        <div class=\"ols-definition-box\">\n          <p><strong>Further substitution:<\/strong> continued replacement of hydrogen atoms by halogen atoms after the first substitution product has already formed.<\/p>\n        <\/div>\n\n        <div class=\"ols-warning-box\">\n          <p><strong>Exam focus:<\/strong> Further substitution is most likely when chlorine is in excess. The product mixture becomes less pure because several chlorinated products can form.<\/p>\n        <\/div>\n      <\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: Stopping at the First Product<\/h2>\n<p>Choose the reaction mixture that gives the purest first product.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-149\" class=\"h5p-iframe\" data-content-id=\"149\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Further Substitution MCQ: Stopping at the First Product\"><\/iframe><\/div><\/div>\n<\/section>\n\n      <article class=\"ols-note-card green\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">4<\/div>\n          <h2>Products Formed During Further Substitution<\/h2>\n        <\/div>\n\n        <p>Starting from methane, one hydrogen can be replaced at a time. Each substitution introduces one chlorine atom and forms one molecule of hydrogen chloride.<\/p>\n        <p>The sequence of possible products is shown below.<\/p>\n\n        <div class=\"ols-table-wrap\">\n          <table class=\"ols-table\">\n            <thead>\n              <tr>\n                <th>Stage<\/th>\n                <th>Organic product<\/th>\n                <th>Name<\/th>\n                <th>What has happened?<\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr>\n                <td data-label=\"Stage\"><strong>First substitution<\/strong><\/td>\n                <td data-label=\"Organic product\">CH<sub>3<\/sub>Cl<\/td>\n                <td data-label=\"Name\">Chloromethane<\/td>\n                <td data-label=\"What has happened?\">One H atom in methane has been replaced by Cl.<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Stage\"><strong>Further substitution<\/strong><\/td>\n                <td data-label=\"Organic product\">CH<sub>2<\/sub>Cl<sub>2<\/sub><\/td>\n                <td data-label=\"Name\">Dichloromethane<\/td>\n                <td data-label=\"What has happened?\">A second H atom has been replaced by Cl.<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Stage\"><strong>Further substitution<\/strong><\/td>\n                <td data-label=\"Organic product\">CHCl<sub>3<\/sub><\/td>\n                <td data-label=\"Name\">Trichloromethane<\/td>\n                <td data-label=\"What has happened?\">A third H atom has been replaced by Cl.<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Stage\"><strong>Complete substitution<\/strong><\/td>\n                <td data-label=\"Organic product\">CCl<sub>4<\/sub><\/td>\n                <td data-label=\"Name\">Tetrachloromethane<\/td>\n                <td data-label=\"What has happened?\">All four H atoms have been replaced by Cl.<\/td>\n              <\/tr>\n            <\/tbody>\n          <\/table>\n        <\/div>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Remember:<\/strong> The more excess chlorine present, the greater the chance that chlorinated products undergo further substitution.<\/p>\n        <\/div>\n      <div class=\"ols-figure-card ols-zoom-pop\">\n<div class=\"ols-figure-image\">\n<a class=\"ols-image-fullscreen-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t4-img-38-substitutionstaircase.jpg\" target=\"_blank\" rel=\"noopener\" aria-label=\"Open image fullscreen\">\n<img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t4-img-38-substitutionstaircase.jpg\" alt=\"Staircase from CH\u2084 down to CCl\u2084 in four steps, each using Cl\u2082 and releasing HCl, with names and the overall equation\" data-fullscreen-src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t4-img-38-substitutionstaircase.jpg\">\n<\/a>\n<\/div>\n<div class=\"ols-figure-caption\"><p>Each step down the ladder replaces one more H by Cl and forms one more HCl.<\/p><\/div>\n<\/div>\n<\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: The Products from Ethane<\/h2>\n<p>Type the formulae of the products formed as ethane is chlorinated further.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-731\" class=\"h5p-iframe\" data-content-id=\"731\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Further Substitution Fill In: The Chlorinated Products of Ethane\"><\/iframe><\/div><\/div>\n<\/section>\n\n      <article class=\"ols-note-card purple\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">5<\/div>\n          <h2>Propagation Steps Leading to Further Substitution<\/h2>\n        <\/div>\n\n        <p>Further substitution can be explained using the same propagation logic as the first chlorination step. A chlorine radical removes a hydrogen atom from chloromethane, producing a chloromethyl radical.<\/p>\n        <p>The chloromethyl radical then reacts with chlorine to form dichloromethane and regenerate a chlorine radical.<\/p>\n\n        <div class=\"ols-equation-grid\">\n          <div class=\"ols-equation-box\">\n            <p>CH<sub>3<\/sub>Cl + Cl\u2022 \u2192 HCl + \u2022CH<sub>2<\/sub>Cl<\/p>\n          <\/div>\n\n          <div class=\"ols-equation-box\">\n            <p>\u2022CH<sub>2<\/sub>Cl + Cl<sub>2<\/sub> \u2192 CH<sub>2<\/sub>Cl<sub>2<\/sub> + Cl\u2022<\/p>\n          <\/div>\n        <\/div>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Why this is propagation:<\/strong> a chlorine radical is used in the first step and regenerated in the second step, so the chain reaction can continue.<\/p>\n        <\/div>\n      <\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: The Steps That Substitute Again<\/h2>\n<p>Complete the two propagation steps that make the second substitution product.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-148\" class=\"h5p-iframe\" data-content-id=\"148\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Further Substitution Drag: The Two Steps That Make Dichloroethane\"><\/iframe><\/div><\/div>\n<\/section>\n\n      <article class=\"ols-note-card yellow\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">6<\/div>\n          <h2>Overall Equations for Further Substitution<\/h2>\n        <\/div>\n\n        <p>Further substitution can be represented using overall equations. Each additional substitution uses one Cl<sub>2<\/sub> molecule and forms one HCl molecule.<\/p>\n\n        <div class=\"ols-equation-grid\">\n          <div class=\"ols-equation-box\">\n            <p>CH<sub>3<\/sub>Cl + Cl<sub>2<\/sub> \u2192 CH<sub>2<\/sub>Cl<sub>2<\/sub> + HCl<\/p>\n          <\/div>\n\n          <div class=\"ols-equation-box\">\n            <p>CH<sub>2<\/sub>Cl<sub>2<\/sub> + Cl<sub>2<\/sub> \u2192 CHCl<sub>3<\/sub> + HCl<\/p>\n          <\/div>\n\n          <div class=\"ols-equation-box\">\n            <p>CHCl<sub>3<\/sub> + Cl<sub>2<\/sub> \u2192 CCl<sub>4<\/sub> + HCl<\/p>\n          <\/div>\n        <\/div>\n\n        <p>If methane is fully chlorinated to tetrachloromethane, all four hydrogen atoms are replaced.<\/p>\n\n        <div class=\"ols-equation-box\">\n          <p>CH<sub>4<\/sub> + 4Cl<sub>2<\/sub> \u2192 CCl<sub>4<\/sub> + 4HCl<\/p>\n        <\/div>\n      <\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: Balance the Overall Equation<\/h2>\n<p>Balance each overall equation on paper, then flip the card to check.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-150\" class=\"h5p-iframe\" data-content-id=\"150\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Further Substitution Flip Cards: Balancing the Overall Equations\"><\/iframe><\/div><\/div>\n<\/section>\n\n      <article class=\"ols-note-card\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">7<\/div>\n          <h2>Exam Clues and Common Mistakes<\/h2>\n        <\/div>\n\n        <p>Exam questions often test whether you understand why free-radical substitution does not usually give one pure product when chlorine is in excess.<\/p>\n        <p>The key point is that chlorinated products still contain C-H bonds, so they can react further under the same free-radical conditions.<\/p>\n\n        <div class=\"ols-table-wrap\">\n          <table class=\"ols-table\">\n            <thead>\n              <tr>\n                <th>Question clue<\/th>\n                <th>What it means<\/th>\n                <th>Best exam response<\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr>\n                <td data-label=\"Question clue\"><strong>Chlorine is in excess<\/strong><\/td>\n                <td data-label=\"What it means\">More than one substitution can occur.<\/td>\n                <td data-label=\"Best exam response\">State that further hydrogen atoms can be replaced by chlorine.<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Question clue\"><strong>A mixture of products forms<\/strong><\/td>\n                <td data-label=\"What it means\">Different numbers of H atoms have been substituted.<\/td>\n                <td data-label=\"Best exam response\">Name or write formulae such as CH<sub>2<\/sub>Cl<sub>2<\/sub>, CHCl<sub>3<\/sub> and CCl<sub>4<\/sub>.<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Question clue\"><strong>Asked for an overall equation<\/strong><\/td>\n                <td data-label=\"What it means\">Show the net reaction, not the radical mechanism.<\/td>\n                <td data-label=\"Best exam response\">For full substitution, write CH<sub>4<\/sub> + 4Cl<sub>2<\/sub> \u2192 CCl<sub>4<\/sub> + 4HCl.<\/td>\n              <\/tr>\n            <\/tbody>\n          <\/table>\n        <\/div>\n\n        <div class=\"ols-warning-box\">\n          <p><strong>Common mistake:<\/strong> Do not stop at CH<sub>3<\/sub>Cl when chlorine is in excess. The question is asking you to consider continued substitution and the resulting product mixture.<\/p>\n        <\/div>\n      <div class=\"ols-figure-card ols-zoom-pop\">\n<div class=\"ols-figure-image\">\n<a class=\"ols-image-fullscreen-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t4-img-39-productmixture.jpg\" target=\"_blank\" rel=\"noopener\" aria-label=\"Open image fullscreen\">\n<img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t4-img-39-productmixture.jpg\" alt=\"Two flasks compared: excess methane gives mainly CH\u2083Cl, excess chlorine gives more CH\u2082Cl\u2082, CHCl\u2083 and CCl\u2084\" data-fullscreen-src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t4-img-39-productmixture.jpg\">\n<\/a>\n<\/div>\n<div class=\"ols-figure-caption\"><p>Further substitution, position isomers and termination by-products all lower the yield of one product.<\/p><\/div>\n<\/div>\n<\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: Explain Why the Product Is Impure<\/h2>\n<p>Write a short explanation, then compare it with the mark points and the model answer.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-151\" class=\"h5p-iframe\" data-content-id=\"151\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Further Substitution Explain: Why the Product Is Never Pure\"><\/iframe><\/div><\/div>\n<\/section>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: Further Substitution Summary<\/h2>\n<p>Pull the whole page together by choosing the accurate statement in each round.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-1291\" class=\"h5p-iframe\" data-content-id=\"1291\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Further Substitution Summary: New Molecules, Same Chain Steps\"><\/iframe><\/div><\/div>\n<\/section>\n\n      \n\n      <section class=\"ols-faq-card\">\n        <h2>Further Substitution FAQs<\/h2>\n        <p>Review the key points about continued substitution in free-radical chlorination.<\/p>\n\n        <div class=\"ols-faq-list\">\n          <div class=\"ols-faq-item\">\n            <h3>What is further substitution?<\/h3>\n            <p>Further substitution is the continued replacement of hydrogen atoms by chlorine atoms after the first substitution product has already formed.<\/p>\n          <\/div>\n\n          <div class=\"ols-faq-item\">\n            <h3>Why does excess chlorine lead to further substitution?<\/h3>\n            <p>Excess chlorine provides enough chlorine molecules and chlorine radicals for chlorinated products such as CH<sub>3<\/sub>Cl to react again, replacing more hydrogen atoms.<\/p>\n          <\/div>\n\n          <div class=\"ols-faq-item\">\n            <h3>Which products can form when methane reacts with excess chlorine?<\/h3>\n            <p>A mixture may form, including CH<sub>3<\/sub>Cl, CH<sub>2<\/sub>Cl<sub>2<\/sub>, CHCl<sub>3<\/sub> and CCl<sub>4<\/sub>, depending on how many hydrogen atoms are replaced.<\/p>\n          <\/div>\n\n          <div class=\"ols-faq-item\">\n            <h3>What is the overall equation for complete chlorination of methane?<\/h3>\n            <p>The overall equation is CH<sub>4<\/sub> + 4Cl<sub>2<\/sub> \u2192 CCl<sub>4<\/sub> + 4HCl.<\/p>\n          <\/div>\n\n          <div class=\"ols-faq-item\">\n            <h3>Why is a mixture of products formed?<\/h3>\n            <p>A mixture forms because partially chlorinated products still contain C-H bonds, so they can undergo further free-radical substitution.<\/p>\n          <\/div>\n        <\/div>\n      <\/section>\n\n      <!-- author card (moved to the end, 10 Oct 2026) -->\n      <div class=\"ols-author\">\n          <img decoding=\"async\" class=\"ols-author-avatar-img\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/Author-Profile.jpeg\" alt=\"Dr. Mohammed Al-Fatah\">\n          <div class=\"ols-author-content\">\n            <h2 class=\"ols-author-title\">Written by: Dr. Mohammed Al-Fatah<\/h2>\n            <p class=\"ols-author-description\">Chemistry specialist revision notes for A Level Chemistry.<\/p>\n            <a class=\"ols-linkedin-pill\" href=\"https:\/\/www.linkedin.com\/in\/doctormohammedfatah\/\" target=\"_blank\" rel=\"noopener noreferrer\">\n              <svg class=\"ols-linkedin-icon\" viewBox=\"0 0 24 24\" fill=\"currentColor\" aria-hidden=\"true\">\n                <path d=\"M4.98 3.5C4.98 4.88 3.86 6 2.48 6S0 4.88 0 3.5 1.12 1 2.48 1s2.5 1.12 2.5 2.5zM.5 8h4V24h-4V8zm7 0h3.8v2.2h.1c.5-.9 1.8-2.2 3.9-2.2 4.2 0 5 2.8 5 6.4V24h-4v-7.6c0-1.8 0-4.2-2.6-4.2s-3 2-3 4v7.8h-4V8z\"\/>\n              <\/svg>\n              View LinkedIn Profile\n            <\/a>\n          <\/div>\n        <\/div>\n\n\n      <section class=\"ols-related-card\">\n        <h2>Related Topics<\/h2>\n        <p>Continue your revision with the linked areas of free-radical substitution and alkane chemistry.<\/p>\n        <div class=\"ols-related-grid\">\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/free-radical-substitution\/\">Free Radical Substitution<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/initiation\/\">Initiation<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/propagation\/\">Propagation<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/termination\/\">Termination<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/fuel\/combustion\/\">Combustion<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/alkene-bonding\/\">Alkenes<\/a>\n        <\/div>\n      <\/section>\n\n            <!-- OLS Author Copyright Footprint \/ Attribution Card -->\n      <section class=\"ols-attribution-card ols-attr-std\" aria-label=\"Copyright notice\">\n<style id=\"ols-attribution-card-css\">.ols-attribution-card.ols-attr-std{background:linear-gradient(135deg,#ffffff,#f8fbff);border:1px solid rgba(28,36,75,0.14);border-radius:28px;box-shadow:0 18px 45px rgba(28,36,75,0.10);padding:34px;margin:24px 0;overflow:hidden;font-family:Poppins,Arial,sans-serif;box-sizing:border-box}.ols-attribution-card.ols-attr-std *{box-sizing:border-box}.ols-attribution-card.ols-attr-std p{margin:0;font-size:14px;line-height:1.65;font-weight:300;color:#667085}.ols-attribution-card.ols-attr-std strong{font-weight:700;color:#1C244B}@media (max-width:760px){.ols-attribution-card.ols-attr-std{padding:24px 18px;border-radius:22px}}<\/style>\n<p><strong>Copyright notice:<\/strong> This OLS revision content, including the explanations, layout, diagrams, tables and embedded learning structure, is authored for Online Learning System by Dr. Mohammed Al-Fatah. It may not be copied, reproduced, redistributed or adapted without written permission.<\/p>\n<\/section>\n\n      <script type=\"application\/ld+json\">\n{\n    \"@context\": \"https:\/\/schema.org\",\n    \"@graph\": [\n        {\n            \"@type\": \"WebPage\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/further-substitution\/#webpage\",\n            \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/further-substitution\/\",\n            \"name\": \"Further Substitution | Free Radical Substitution | A Level Chemistry Revision Notes\",\n            \"description\": \"Edexcel A Level Chemistry revision notes on further substitution in free-radical chlorination, including excess chlorine, product mixtures, CH2Cl2, CHCl3, CCl4 and the overall equation for complete 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